Copy sheet feed tray raising and lowering device for duplicator or the like

ABSTRACT

A copy sheet feed tray operating device comprising an operation lever, pivotally supported by a side plate of the duplicating machine in which it is incorporated and movable from a first position to second and third positions, and suitable operating mechanisms whereby pivoting of the operation lever from the first position to the second position moves the copy sheet feed tray downwardly and the copy sheet feed roller upwardly, thereby permitting the placing of a predetermined number of copy sheets on the tray. Shifting of the operation lever from the second position to the third position moves the copy sheet feed tray upwardly so as to bring the top of a new stack of copy sheets on the tray into pressing engagement with the copy sheet feed roller. The force with which the copy sheet feed roller presses against the stack of copy sheets on the tray is automatically adjusted to an optimum level so that it is possible to feed each copy sheet under optimum conditions without requiring further adjustments. When the operation lever is released, it automatically returns to the first position.

United States Patent 1 Suzuki 1 Apr. 3, 1973 [54] COPY SHEET FEED TRAY RAISING AND LOWERING DEVICE FOR DUPLICATOR OR THE LIKE [75] Inventor:

[73] Assignee: Ricoh Co. Ltd., Tokyo, Japan [22] Filed: Dec. 20, 1971 [21] Appl. No.: 209,642

Minoru Suzuki, Yokohama, Japan [30] Foreign Application Priority Data Primary ExaminerI-larvey C. Hornsby Assistant Examiner-James W. Miller Attorney-Henry T. Burke et al.

[57] ABSTRACT A copy sheet feed tray operating device comprising an operation lever, pivotally supported by a side plate of the duplicating machine in which it is incorporated and movable from a first position to second and third positions, and suitable operating mechanisms whereby pivoting of the operation lever from the'first position to the second position moves the copy sheet feed tray downwardly and the copy sheet feed roller upwardly, thereby permitting the placing of a predetermined number of copy sheets on the tray. Shifting of the operation lever from the second position to the third position moves the copy sheet feed tray upwardly so as to bring the top of a new stack of copy sheets on the tray into pressing engagement with the copy sheet feed roller. The force with which the copy sheet feed roller presses against the stack of copy sheets on the tray is automatically adjusted to an optimum level so that it is possible to feed each copy sheet under optimum conditions without requiring further adjustments. When the operation lever is released, it automatically returns to the first position.

10 Claims, 9 Drawing Figures PATENTEUAPR 3 I973 SHEET 1 0F 3 INVENTOR. MAM/w 5020/0 BY BACKGROUND OF THE INVENTION This invention relates to a copy sheet feed tray raising and lowering device for duplicating machines or the like.

In mimeograph printing machines, offset printing machines and the like, the copy sheet feed tray is gradually moved upwardly by a known copy sheet feed tray elevating device coupled to the printing machine as the number of copy sheets on the tray gradually decreases with the progress of printing operation. In such devices, the command to move upwardly is generally given when a detection lever operatively associated with the copy sheet feed roller moves downwardly.

When a new stack of copy sheets is placed on the copy sheet feed tray after all the copy sheets of the prior stack have been fed or only a small number of them remain, it has hitherto been customary in the known device to manually and separately perform in different steps the operations of lowering the copy sheet feed tray, raising the copy sheet feed roller, raising the copy sheet feed tray to a predetermined level after a new stack of copy sheets has been placed thereon, lowering the copy sheet feed roller into pressing engagement with the top of the stack of copy sheets, and adjusting the force with which the copy sheet feed roller presses against the top of the stack of copy sheets. This has caused inconvenience to the operator because it is troublesome and time-consuming to perform such operations separately, and this greatly reduces printing efficiency.

SUMMARY OF THE INVENTION This invention embodies a copy sheet feed tray raising and lowering device for duplicating machines or the like comprising suitable mechanism actuated by an operation lever which is movable from a first position to second and third positions. When the operation lever is shifted from the first position to the second position, the mechanism causes a detection lever to be moved in pivotal motion, a copy sheet feed roller to move upwardly, and a ratchet wheel for moving the copy sheet feed tray upwardly to be released, thereby permitting the copy sheet feed tray to move downwardly by its own weight to its lower position for the placing of a new stack of copy sheets thereon. When the operation lever is moved from the second position to the third position, the ratched wheel is rotated so as to move the copy sheet feed tray upwardly into pressing engagement with the copy sheet feed roller. When the operation lever is released, it automatically returns to the first position and the force with .which the copy sheet feed roller presses against the top of the new stack of copy sheets is automatically adjusted to an optimum level so that it is possible to feed each copy sheet under optimum conditions without requiring further adjustments. This invention thus permits the copy sheet feed tray to be moved upwardly and downwardly by merely shifting the operation lever from the first position to the second and third positions, and the additional operation of adjusting the force with which the copy sheet feed roller presses against the top of the new stack of copy sheets on the copy sheet feed tray can be eliminated.

According to this invention, the need to manually perform the operations of raising the copy sheet feed roller, raising the copy sheet feed tray and lowering the copy sheet feed tray separately as is done in conventional devices of this type is eliminated. These operations can be performed by merely shifting the operation lever from the first position to the second and third positions. Furthermore, the operation of adjusting the force with which the copy sheet feed roller presses against the top of the new stack of copy sheets on the copy sheet feed tray can be eliminated, thereby simplifying the operation of placing a new stack of copy sheets on the copy sheet feed tray and greatly increasing printing efficiency.

BRIEF EXPLANATION OF THE DRAWINGS FIG. 1 is a side view of a conventional copy sheet feed tray for rotary mimeograph printing machines in which the present invention can be incorporated.

FIG. 2 is a side view of the copy sheet feed tray raising and lowering device embodying the present invention.

FIGS. 3 to 5 are views illustrating the operation of the device shown in FIG. 2.

FIG. 6 is a side view of the segmental gear and the ratchet wheel portion of the device shown in FIG. 2.

FIG. 7 is a view illustrating the operation of the ratchet wheel and the feed roller force adjusting means.

FIG. 8 is a perspective view of the boss of the ratchet wheel shown in FIG. 7; and

FIG. 9 is a fragmentary sectional view in plan of the ratchet wheel portion shown in FIG. 6.

DESCRIPTION OF A PREFERRED EMBODIMENT OF THE INVENTION While this invention can have application in the copy sheet feed tray means of offset printing machines or rotary mimeograph printing machines, or the like, the invention will be described with reference to an embodiment incorporated in a rotary mimeograph printing machine.

A rotary mimeograph printing machine generally comprises a pair of (upper and lower) master cylinders having a screen entrained thereover, a pair of ink form rollers each maintained in pressing engagement with one of the two master cylinders, and a pressure roller maintained in pressing engagement with the lower master cylinder through the screen. Printing is carried out as a copy sheet fed by the copy sheet feed device is pressed by the pressure roller against the original to be duplicated which is mounted on the screen beforehand.

In FIG. 1, such a screen 5 having an original 4 to be duplicated mounted thereon is shown entrained about a master cylinder 3 supported by a shaft 2 connected to a machine side plate '1 (shown in FIG. 2). An ink form roller 6 is maintained in pressing engagement with the peripheral surface of master cylinder 3.

A pressure roller 9 mounted by a shaft at a free end of an arm 8 which is supported by a shaft 7 connected to the machine side wall, is adapted to come into pressing engagement with master cylinder 3 only when a copy sheet is fed into engagement with the master cylinder 3 by a pair of delivery rollers 1 1 and 12 which are supported by shafts connected to the machine side plate.

A copy sheet guide plate 13, and a wall 14 are also secured to the side plate 1. Wall 14 is formed therein with an opening 14a through which projects leftwardly in the figure a portion of a drive pinion 16 mounted on the side plate 1 by a shaft 15. A rack 17a of a rack plate 17 is maintained in meshing engagement with the projecting portion of pinion 16.

Cutouts 21a and 21b formed in copy sheet feed tray 21 engage pins 18 and 19, respectively, which are attached to rack plate 17. The pin 19 projecting inwardly of rack plate 17 and with a pin 22, attached to an upper portion of rack plate 17, is loosely received in a vertical slot 23 formed in the side plate 1. Copy sheet feed tray 21 is provided with a guide side wall 24 which brings side edges of copy sheets 25 piled in a stack on copy feed tray 21 into alignment with one another. Front edges of the copy sheets 25 facing rightwardly in the figure are lightly held in place by a comer separator 26.

A copy sheet feed roller 28 supported by a shaft 27 is maintained in engagement with the top of the stack of copy sheets 25. Shaft 27 is mounted at a free end of a supporter 29 which is secured at its base to a shaft 31 rotatably connected to the side plate 1. The shaft 31 extends outwardly through the side plate 1 and has secured to the projecting end portion thereof a base 32b of a detection lever 32 as shown in FIG. 2. Supporter 29 and detection lever 32 operate in a substantially integral manner with each other.

On the other side of the side plate, as shown in FIG. 2, detection lever 32 is formed with a tab portion 32a having an opening for threadably receiving therein an adjusting screw 33. Adjusting screw 33 is maintained in engagement with a tab portion 34a formed on a charge member 34 which is supported by a shaft 35 connected to the side wall 1. A spring 37 is mounted between a first lock member 36, also supported by shaft 35, and charge member 34 so that another tab portion 34b of charge member 34 is maintained in pressing engagement with sideedge 36b of first lock member 36 by the biasing force of spring 37.

Adjacent lock member 36 is a follower 39 which is supported by a shaft 38 connected to the side wall 1 and urged to pivot counter-clockwise by the biasing force of a spring 43 which is mounted at one end on a pin 41 attached to the side plate 1 and at the other end on a pin 42 attached to follower 39. counterclockwise pivotal movement of follower 39 is normally precluded by the pressing engagement of an extended portion 390 formed on follower 39 with an offset. portion 36a formed on the end of first lock member 7 Above follower 39 .is a drive cam 44 mounted on shaft 2 supporting master cylinder 3 and adapted to be rotated clockwise, that is, in a direction opposite to the direction of rotation of master cylinder 3 by suitable reverse rotation means. A roller 46 mounted at a free end of follower 39 by a shaft 45 is engaged by cam 44, moving follower 39 slightly against the action of spring 43 each time cam 44 makes one complete revolution, soas to reduce the force with which extended portion 39a is maintained in pressing engagement with offset portion 36a.

A feed pawl 48 pivotally connected to follower 39 by a shaft 47 is urged to pivot clockwise about shaft 47 by the biasing force of a spring 49 which is mounted at one end on a pin 51 attached to the side plate 1 and at the other end on a pin 48a attached to the pawl 48. Feed pawl 48 is formed at its front end with a pawl member 48b which is maintained in pressing engagement with the peripheral edge of a ratchet wheel 55 by the biasing force of spring 49. A reverse rotation check pawl 53 is pivotally supported by a shaft 54 connected to the side plate 1 and has a .pawl member 53a at its front end which is maintained in pressing engagement with the peripheral edge of ratchet wheel 55 by the biasing force of a spring 53b shown in FIG. 6.

Cutouts 56a and 56b, shown more clearly in FIG. 8, are formed in a boss 56 of ratched wheel 55. Received in the two cutouts are opposite ends of a cotter pin 58 which secures a pinion 57 to shaft 15 (see FIG. 9). With this arrangement, ratchet wheel 55 is mounted on shaft 15 such that it can rotate freely relative to shaft 15 within limits defined by the side surfaces of the two cutouts 56a and 56b in boss 56 which abut against cotter pin 58 after permitting a degree of play as shown in FIG. 7.

Returning to FIG. 2, a segmental gear 59 is maintained in meshing engagement with pinion 57 which segmental gear is pivotally supported at its base by a shaft 61 connected to the side plate 1. A biasing spring 62 mounted on shaft 61 is maintained by a free end 62a thereof in pressing engagement with a tab portion 59a formed on segmental gear 59. Spring 62 is maintained by the other end 62b thereof in engagement with a tab portion 63a formed in a click stopper 63 pivotally supported by a shaft 64 connected to the side wall 1. A roller 65 mounted by a shaft at a free .end of click stopper 63 is maintained in pressing engagement in a recess 67 formed in an actuation cam 66, mounted on shaft 61, by the biasing force of spring 62.

An operation lever 71 in accordance with the present invention extends from an actuation cam 66 which has a tab portion 66a that is brought, by the weight of lever 71, into engagement with a straight arm portion 620 of spring 62.

Actuation cam 66 is formed with an opening 72 into which extends a roller 73 mounted on a shaft at a free end of detection lever 32. As subsequently to be described, roller 73 may be brought into engagement with a downwardly facing arcuate inner edge portion 72a an upwardly facing straight edge portion 72b and a valley 72c contiguous with edge portions 72a and 72b, as operation lever 71 is operated.

A release cam 74 for releasing pawl members 53a and 48b from engagement with ratchet wheel 55 is mounted on the shaft 15 which ratchet wheel 55 is mounted. Release cam. 74 is urged to rotate clockwise by the biasing force of a spring 76, whose opposite ends are mounted on a pin 75 attached to a short arm of cam 74 and shaft 35 respectively; The short arm is maintained by one side edge in pressing engagement with a pin 77, attached to actuation cam 66, by the biasing force of spring 76.

Referring to FIG. 1 again, in operation, copy-sheet feed roller 28 intermittently rotates in the direction of the arrow as the copy sheet feed mechanism (not shown) is actuated to feed one copy sheet 25 after another to the pair of delivery rollers 11 and 12 which deliver each copy sheet between master cylinder 3 and pressure roller 9, so that printing is carried out.

Copy sheet feed roller 28 gradually moves downwardly as the copy sheets 25 on copy sheet feed tray 21 are reduced in number, with supporter 29 pivoting counter-clockwise as shaft 31 angularly rotates in the same direction. During the pivotal movement of supporter 29, detection lever 32 shown in FIG. 2, which is substantially integral in operation with supporter 29 as aforesaid, pivots in the same direction and causes charge member 34 to pivot counterclockwise, so that some energy of resilience is gradually stored in spring 37. When the energy of resilience stored in spring 37 is low in magnitude, counter-clockwise pivotal movement of lock member 36 does not occur even if follower 39 is caused to slightly pivot clockwise by the action of cam 44 and the force with which extended portion 39a is maintained in pressing engagement with offset portion 36a is reduced. Thus, lock member 36 continues to lock follower 39.

When the energy of resilience stored in spring 37 increases in magnitude with a reduction of the number of copy sheets 25 on copy sheet feed tray 21 by, for example, about sheets, then lock member 36 is caused to pivot counter-clockwise about shaft 35 by the biasing force of spring 37 when the force with which follower 39 is maintained in engagement with lock member 36 is reduced, thereby releasing follower 39 from engagement with lock member 36. As a result, follower 39 makes one pivotal motion about shaft 38 in slaved relation to the rotation of cam 44. By this pivotal movement of follower 39, feed pawl 48 angularly rotates ratchet wheel 55 clockwise a predetermined amount, and cotter pin 58 maintained in pressing engagement with the boss 56 of ratchet wheel 55 as shown in FIG. 7 pivots clockwise as shaft rotates in the same direction.

As aforementioned, pinion 57 maintained in meshing engagement with segmental gear 59 and drive pinion 16 maintained in meshing engagement with rack plate 17 shown in FIG. 1 are secured to shaft 15. Because of this arrangement, rack plate 17 and copy sheet feed tray 21 mounted thereon intermittently move upwardly as ratchet wheel 55 angularly rotates clockwise. Upward movement of copy sheet feed tray 21 is repeated each time about 10 copy sheets are removed from the stack of copy sheets on copy sheet feed tray 21. Segmental gear 59 pivots counter-clockwise as shown in FIG. 3 each time copy sheet feed tray 21 moves upwardly.

When all the copy sheets on copy sheet feed tray 21 are fed, it is necessary to place thereon a fresh supply of copy sheets. To this end, it is required to lift copy sheet feed roller 28, lower copy sheet feed tray 21 and raise copy sheet feed tray 21 after a new stack of copy sheets is placed thereon. As aforesaid, these operations have hitherto been performed separately by hand in devices of the prior art. According to this invention, these operations can be readily performed by shifting operation lever 71 upwardly and downwardly. Operation 'of the device according to this invention will now be set forth.

In FIG. 2, operation lever 71 is shown disposed in a first position in which it is inoperative and copy sheets are fed one after another to perform a printing operation. When it is desired to place a fresh supply of copy sheets on the copy sheet feed tray, operation lever 71 is' shifted clockwise to a second position shown in FIG. 4. As operation lever 71 is moved from the first position shown in FIG. 2 to the second position shown in FIG. 4, the roller 73 of detection lever 32 is pushed upwardly by the upwardly facing straight edge portion 72b of action cam 66 and into valley 720 as shown in FIG. 4. Clockwise pivotal movement of detection lever 32 results in clockwise pivotal movement of copy sheet feed roller supporter 29 shown in FIG. 1 which is substantially integral in operation with detection lever 32, so that copy sheet feed roller 28 is moved upwardly to a dash-and-dot line position 28a in FIG. 1.

On the other hand, release cam 74 is caused to pivot counterclockwise by pin 77 during the clockwise pivotal movement of actuation cam 66. This results in reverse rotation check pawl 53 and feed pawl 48 being engaged by and riding on an outer side edge 74a of cam 74, so that pawl members 48b and 53a are released from engagement with ratchet wheel 55 as shown in FIG. 4. When ratchet wheel 55 and shaft 15 are thus released, copy sheet feed tray 21 which is mounted on the rack plate 17 in meshing engagement with the pinion 16 shown in FIG. 1 is free to move downwardly by its own weight to a predetermined position. At the same time, the segmental gear 59 in meshing engagement with pinion 57 angularly rotates and returns to a position shown in FIG. 4 in conjunction with the downward movement of copy sheet feed tray 21.

It will thus be evident that by merely shifting operation lever 71 to the second position shown in FIG. 4, it is possible to simultaneously cause copy sheet feed roller 28 to move upwardly and copy sheet feed tray 21 to move downwardly so as to permit placing of a new stack of copy sheets on the 'copy sheet feed tray. When operation lever 71 is shifted to this second position, the roller 65 of click stopper 63 drops into another recess 68 formed in actuation cam 66, thereby holding operation lever 71 in place while in the second position shown in FIG. 4.

One has only to shift operation lever 71 from the second position shown in FIG. 4 to the third position shown in FIG. 5 to raise copy sheet feed tray 21 to 'a' predetermined position after a new stack of copy sheets has been piled thereon. Angular rotation of actuation cam 66 from its position shown in FIG. 2 to its position shown in FIG. 5 causes tab portion 66a to move the straight arm portion 620 of spring 62 and one side edge 59b (shown in FIG. 3) of segmental gear 59 counterclockwise. As a result, click stopper 63 angularly rotates till its lower end 63b abuts against a stopper 69 affixed to the side plate 1, thereby releasing roller 65 from pressing engagement with actuation cam 66.

Meanwhile, counter-clockwise angular rotation of segmental gear 59 causes the drive pinion 16, shown FIG. 1, which is substantially integral in operation with pinion 57, to angularly rotate clockwise, thereby raising rack plate 17 and copy sheet'feed tray 21.

As copy sheet feed tray 21 draws close to its upper position in its upward movement, the top of the new stack of copy sheets 25 thereon engages and upwardly moves copy sheet feed roller 28. This causes the supporter 29 which supports copy sheet feed roller 28 and the detection lever 32 to slightly pivot clockwise to bring the roller 73 of detection lever 32 into abutting engagement with the downwardly facing arcuate inner edge portion 72a of actuation cam 66 as shown in FIG. 5.

The position at which roller 73 comes into abutment with the arcuate edge portion 72a will vary depending on the number of copy sheets piled in a stack on copy sheet feed tray 21. The smaller number of copy sheets, the greater is the, counter-clockwise pivotal movement of operation lever 71., Regardless of the extent, however, the counter-clockwise angular movement of operation lever 71 is terminated as roller 73 is forcibly brought into abutting engagement with arcuate inner edge portion 72a. The force with which roller 73 is brought into abutting engagement with inner edge portion 72a is produced by the action of the copy sheets on copy sheet feed tray 21 upwardly pushing copy sheet feed roller 28 and the manual force exerted on lever 71 in moving it from the second to the third position. Therefore, the copy sheets are brought into pressing engagement with copy sheet feed roller 28 with a significant force if operation lever 71 is pivoted till it stops. It is impossible to perform a smooth copy sheet feed operation so long as the copy sheets and copy sheet roller 28 are in this state. According to this invention, means is provided for automatically lowering copy sheet feed tray 21 to an optimum position for carrying out copy sheet feed smoothly without requiring further adjustments. This feature will now be described.

As actuation cam 66 angularly rotates from its position shown in FIG. 4 to its position shown in FIG. 5, release cam 74 angularly rotates clockwise till it stops when the arm 74b thereof abuts against a stopper 78 affixed to the side plate 1. This angular rotation of release cam 74 brings the pawl members 53a and 48b of check pawl 53 and feed pawl 48 respectively into engagement with ratchet 55 again as shown in FIG. 5. Meanwhile, when segmental gear 59 angularly rotates counterclockwise, the cotter pin 58 attached to pinion 57 turns the boss 56 of ratchet wheel 55 clockwise in a manner shown in FIG. 6. Therefore, if operation lever 71 is released when it has been brought to its position shown in FIG. in which the copy sheets on copy sheet feed tray 21 are brought into pressing engagement with copy sheet feed roller 28, shaft and cotter pin 58 will be slightly rotated in the reverse direction or counterclockwise by the weight of copy sheet feed tray 21. This reverse movement is stopped by cotter pin 58 abutting against the other wall surfaces of cutouts 56a and 56b as shown in FIG. 7.

g The amount of reverse movement of cotter pin 58 may thus be varied by regulating the dimensions of the cutouts 56a and 56b. As cotter pin 58 moves in the reverse direction as aforesaid, the pinion 16 secured to shaft 15 as shown in FIG. .1 rotates counterclockwise, thereby causing copy sheet feed tray 21 to move slightly downwardly. The distance of this downward movement corresponds to the thickness of several number of copy sheets, so that the force with which copy sheet feed roller 28 presses against the top of the stack of copy sheets is brought to an optimum level which permits the carrying out of copy sheet feeding under satisfactory conditions.

If operation lever 71 is released when it is in the position shown in FIG. 5, actuation cam 66, which is integral with lever 71, will be caused to angularly rotate clockwise by thebiasing force of spring 62 till it stops at a position shown in FIG. 2 in which one end 62b of the spring abuts against the tab portion 63a of click stopper 63. This automatically returns operation lever 71 to the first position. Click stopper 63 is caused to angularly rotate counter-clockwise by the biasing force of spring 62 to bring roller 65 into engagement in the recess 67 of actuation cam 66 again, so as to thereby hold operation lever 71 in place in the first position.

What is claimed is:

1. Apparatus for raising and lowering a copy sheet feed tray in a duplicating machine comprising:

a. 'means-for elevationally supporting a copy sheet feed tray;

b. a copy sheet feed roller for feeding copy-sheets in succession from a stack of copy sheets on said feed tray to the machine;

0. means for elevating said feed tray supporting means;

(1. a rotatable shaft for operating said elevating means;

e. a ratchet wheel for rotating said shaft;

f. a feed pawl for advancing said ratchet wheel;

g. a check pawl for preventing reverse rotation of said ratchet wheel; 7

h. a pivoted supporter for said copy sheet feed roller;

i. a detection lever connected to and pivoted with 4 said supporter;

j. drive means;

k. means responsive to the position of said detection lever for intermittently coupling said feed pawl to said drive means so as to intermittently advance said ratchet wheel to raise the feed tray by operating the shaft and elevating means;

I. an operation lever movable from a first position to second and third positions;

m. first cam means actuated by said operation lever for pivoting said detection lever when said operation lever is shifted to its second position so as to raise said feed roller;

. means for releasing said feed pawl and check pawl from engagement with said ratchet wheel when said operation lever is shifted to its second position so as to permit said feed, tray to descend to its lowest position;

. means connected to said operation lever for rotatingsaid rotatable shaft when the operation lever is shifted to its third position so as to raise said feed tray; and

p. second cam means actuated by said operation lever for preventing the pivoting of said detection lever when said operation lever is in its third position so as to maintain said feed roller in position when said feed tray is raised by the shifting of said operation lever to said third position whereupon said feed roller is urged upwardly by engagement with a stack of copy sheets on said feed tray.

2. Apparatus as in claim 1, wherein said means for intermittently coupling said feed pawl and said drive means comprises:

q. pivotable means actuated by said detection lever;

r. lever means resiliently connected to said pivotable means and pivoted when said pivotable means pivots beyond a predetermined displacement;

s. follower means having said feed pawl mounted thereon and held against pivoting by said lever means; and

t. cam means rotated by said drive means and cooperating with said follower means upon the release of said follower means by said lever means to drive said feed pawl.

3. Apparatus as in claim 1, including:

q. boss means on said ratchet wheel having opposed cut-out portions therein; and

r. pin means fixed to said rotatable shaft and received in said cut-out portions to permit a predetermined amount of play between the rotation of said shaft and said ratchet wheel.

4. Apparatus as in claim 1, wherein said feed pawl and check pawl releasing means comprises:

q. third cam means;

r. spring means for holding said third cam means in inoperative position; and

s. means on said operation lever for engaging said third cam means when said operation lever is shifted to its third position to overcome the force of said spring means and rotate said third cam means to a position to release said pawls.

5. Apparatus as in claim 1, wherein the means connected to said operation lever for rotating said rotatable shaft when the operation lever is shifted to its third position comprises:

q. a segmental gear rotated by said operation lever;

and

r. pinion means on said rotatable shaft cooperating with said segmental gear.

6. Apparatus as in claim 1, wherein said elevating means comprises:

q. a rack on said supporting means; and

r. a pinion cooperating with said rack on said rotatable shaft.

7. Apparatus as in claim 1, including a member on said operation lever having an edge with adjacent recesses therein and a spring loaded roller means riding on the edge of said member and respectively seating in said recesses when said operation lever is in its first and third positions for holding said operation lever in said positions.

8. Apparatus as in claim 7, wherein said member comprises said first and second cam means.

9. Apparatus as in claim 8, wherein said member comprises third cam means for holding said detection lever in the raised position when said operation lever is in its second position.

10. Apparatus as is claim 1, wherein said drive means comprises a continuously rotating cam means operatively connected to a master print cylinder of the duplicating machine. 

1. Apparatus for raising and lowering a copy sheet feed tray in a duplicating machine comprising: a. means for elevationally supporting a copy sheet feed tray; b. a copy sheet feed roller for feeding copy sheets in succession from a stack of copy sheets on said feed tray to the machine; c. means for elevating said feed tray supporting means; d. a rotatable shaft for operating said elevating means; e. a ratchet wheel for rotating said shaft; f. a feed pawl for advancing said ratchet wheel; g. a check pawl for preventing reverse rotation of said ratchet wheel; h. a pivoted supporter for said copy sheet feed roller; i. a detection lever connected to and pivoted with said supporter; j. drive means; k. means responsive to the position of said detection lever for intermittently coupling said feed pawl to said drive means so as to intermittently advance said ratchet wheel to raise the feed tray by operating the shaft and elevating means; l. an operation lever movable from a first position to second and third positions; m. first cam means actuated by said operation lever for pivoting said detection lever when said operation lever is shifted to its second position so as to raise said feed roller; n. means for releasing said feed pawl and check pawl from engagement with said ratchet wheel when said operation lever is shifted to its second position so as to permit said feed tray to descend to its lowest position; o. means connected to said operation lever for rotating said rotatable shaft when the operation lever is shifted to its third position so as to raise said feed tray; and p. second cam means actuated by said operation lever for preventing the pivoting of said detection lever when said operation lever is in its third position so as to maintain said feed roller in position when said feed tray is raised by the shifting of said operation lever to said third position whereupon said feed roller is urged upwardly by engagement with a stack of copy sheets on said feed tray.
 2. Apparatus as in claim 1, wherein said means for intermittently coupling said feed pawl and said drive means comprises: q. pivotable means actuated by said detection lever; r. lever means resiliently connected to said pivotable means and pivoted when said pivotable means pivots beyond a predetermined displacement; s. follower means having said feed pawl mounted thereon and held against pivoting by said lever means; and t. cam means rotated by said drive means and cooperating with said follower means upon the release of said follower means by said lever means to drive said feed pawl.
 3. Apparatus as in claim 1, including: q. boss means on said ratchet wheel having opposed cut-out portions therein; and r. pin means fixed to said rotatable shaft and received in said cut-out portions to permit a predetermined amount of play between the rotation of said shaft and said ratchet wheel.
 4. Apparatus as in claim 1, wherein said feed pawl and check pawl releasing means comprises: q. third cam means; r. spring means for holding said third cam means in inoperative position; and s. means on said operation lever for engaging said third cam means when said operation lever is shifted to its third position to overcome the force of said spring means and rotate said third cam means to a position to release said pawls.
 5. Apparatus as in claim 1, wherein the means connected to said operation lever for rotating said rotatable shaft when the operation lever is shifted to its third position comprises: q. a segmental gear rotated by said operation lever; and r. pinion means on said rotatable shaft cooperating with said segmental gear.
 6. Apparatus as in claim 1, wherein said elevating means comprises: q. a rack on said supporting means; and r. a pinion cooperating with said rack on said rotatable shaft.
 7. Apparatus as in claim 1, including a member on said operation lever having an edge with adjacent recesses therein and a spring loaded roller means riding on the edge of said member and respectively seating in said recesses when said operation lever is in its first and third positions for holding said operation lever in said positions.
 8. Apparatus as in claim 7, wherein said member comprises said first and second cam means.
 9. Apparatus as in claim 8, wherein said member comprises third cam means for holding said detection lever in the raised position when said operation lever is in its second position.
 10. Apparatus as is claim 1, wherein said drive means comprises a continuously rotating cam means operatively connected to a master print cylinder of the duplicating machine. 